The studies proposed here are intended to elucidate the mechanisms by which the dominant follicle and corpus luteum participate in the regulation of follicle growth and between-ovary interaction during the ovarian cycle in cynomolgus monkeys. As a direct continuation of my early work, the studies here will be designed to determine by what mechanism the ovary bearing the cyclic structure subordinates the opposite ovary into a quiescent state, that is, how do the ovaries interact. Three different aspects of this kind of interaction will be examined. First, I will test the hypothesis that the dominant follicle inhibits the growth of other competing follicles by secreting a substance that acts directly on the ovaries to prevent the development of competing follicles. Second, I will test the hypothesis that the corpus luteum inhibits follicle growth on both ovaries by a direct, intraovarian action of progesterone. Third, I will evaluate the importance of specific neural or local vascular links in between-ovary interaction. To accomplish these primary aims I plan to use the cynomolgus monkey in which one ovary has been auto-transplanted to the neck by means of microsurgical vascular reanastomosis as an in vivo experimental model. In a parallel study I plan to perform a computer-assisted reconstruction and stereological analysis of the cynomolgus monkey ovary, already available as H & E stained, serial histological sections, to obtain morphological evidence of follicle-follicle and/or luteal-follicle interaction. Thus, the studies here are intended to contribute to a better understanding of the regulation of the primate ovarian cycle, in general, and of ovulatory follicle growth, in particular. An understanding of the regulation of the size of the final ovulatory quota in this primate will be important in serving as a rational basis for the design of clinical programs of fertility enhancement or regional or global program of population control.